Electron radiographic receptor package with dielectric pieces on a conducting sheet

ABSTRACT

A receptor package for an electron radiography system, in the form of a continuous electrically conducting carrier or backing sheet with electrostatic image receptor pieces mounted thereon at spaced intervals with a separable adhesive permitting removal of the receptor pieces after exposure. A fan or Z fold package and a rolled configuration. A continuous sheet providing transport for the receptor pieces through the imaging chamber and providing the electrical conductivity for the face of the receptor piece opposite the electrostatic image forming face.

United States Patent [1 1 Eseke et al.

[ Mar. 25, 1975 ELECTRON RADIOGRAPI-IIC RECEPTOR PACKAGE WITH DIELECTRIC PIECES ON A CONDUCTING SHEET [75] Inventors: James R. Eseke, Mission Hills;

Stelios B. Papadopoulous. Northridge, both of Calif.

[73] Assignee: Xonics, Inc., Van Nuys, Calif.

[22] Filed: Nov. 28, 1973 [21] Appl. No.: 419,526

[52] US. Cl. 250/315, 250/468 [51] Int. Cl. G0ln 23/04 v [58] Field of Search 250/315 A, 315 R, 468; 354/174 [56] References Cited UNITED STATES PATENTS 3/1958 Walkup 250/315 A Erlichman 354/174 X 3.152.529 lO/l964 3,766,385 lO/l973 Morsell et al 250/3l5 A Primary Eraminer-James W. Lawrence Assistant ExaminerDavis L. Willis Attorney, Agent, or Firm-Harris, Kern, Wallen & Tinsley [57] ABSTRACT A receptor package for an electron radiography system, in the form of a continuous electrically conducting carrier or backing sheet with electrostatic image receptor pieces mounted thereon at spaced intervals with a separable adhesive permitting removal of the receptor pieces after exposure. A fan or Z fold package and a rolled configuration. A continuous sheet providing transport for the receptor pieces through the imaging chamber and providing the electrical conductivity for the face of the receptor piece opposite the electrostatic image forming face.

12 Claims, 6 Drawing Figures PATENTED MAR 25 I975 ELECTRON RADIOGRAPHIC RECEPTOR PACKAGE WITH DIELECTRIC PIECES ON A CONDUCTING SHEET This invention relates to a new and improved package for the dielectric receptor sheet of the type used in electron radiography systems. A typical system which provides for the creation of x-ray images is described in the copending application of Muntz et al, Ser. No. 261,927, filed June 12, 1972, now US. Pat. No. 3,774,029 entitled Radiographic systems with Xerographic Printing, and assigned to the same assignee as the present application. In such a system, an x-ray opaque fluid is utilized between electrodes in an imaging chamber to produce a photoelectric current within the chamber as a function of x-rays entering the chamber. The current is collected on a receptor sheet placed on one of the electrodes, resulting in a latent electrostatic image on the sheet. This latent image is then made visible by developing and fixing, following conventional xerographic techniques.

There are a number of desirable characteristics for the dielectric receptor sheet in an electron radiographic system. The material of the receptor exposed to the latent image charge should have sufficient resistivity to hold that charge without diffusion along the receptor surface, since diffusion results in blurring of the image. Further, the surface of the receptor sheet opposite that on which the electrostatic charge is produced, should be electrically conducting. This conducting surface allows the induced charge in the electrode to transfer to the back of the receptor, thus preventing electrical breakdown from the electrode to the charged receptor as the receptor is removed from the imaging chamber. Also, the surface of the receptor which accepts the image charge should be such as to permit strong bonding of the toner to that surface. In addition, the receptor should be of sufficient rigidity to allow ease of handling as it is moved from imaging chamber to developer and for subsequent handling by radiologists, while also being transparent for viewing the resultant image on light boxes.

In some situations, a single sheet of polyester such as Mylar is used as the receptor sheet. A. multiple layer sheet has anumber of advantages over the single sheet and a preferred design for a multiple layer sheet is disclosed in the copending application of Welkowsky, Ser. No. 398,484, filed Sept. 18, 1973 entitled Electron Radiograph Receptor, and assigned to the same assignee as the present application. This multiple layer receptor sheet comprises a relatively thick transparent dielectric plastic core layer bonded between a relatively'thin dielectric image carrier layer and an antistatic conducting layer. Specific materials and configurations for the various layers are set out in said copending application.

In'the past, individual sheets have been used for the receptor, with each sheet being separately manipulated through the various steps in the picture making process. The present invention is directed to a receptor package with a plurality of the imaging pieces on a continuoussheet providing for ease of storage, installation and transport, while at the same time providingthe desired characteristics of the receptor for use in the imaging chamber. The present invention provides a receptor package for an electron radiography system comprising a length of an electrically conducting sheet having a plurality of pieces of transparent dielectric plastic carried thereon, thus providing the desired multilayer receptor sheet. The plastic pieces on which the electrostatic image and subsequent visual image are formed are attached to the electrical conducting sheet by a separable adhesive permitting removal of the individual plastic pieces from the continuous conducting sheet. Accordingly, it is an object of the present invention to provide such a new and improved receptor package providing both the desired mechanical support and transport characteristics and the desired electrical characteristics in a single package. Other objects, advantages features and results will more fully appear in the course of the following description. The drawing merely shows and the description merely described preferred embodiments of the present invention which are given by way of illustration or example.

In the drawing:

FIG. 1 is a diagram of an electron radiography system including a receptor package or magazine and incorpo rating the presently preferred embodiment of the invention;

FIG. 2 is a vertical sectional view through the magazine of the system of FIG. 1;

FIG. 3 is a top view of a section of the receptor package strip;

FIG. 4 is a view similar to FIG. 3 showing a sprocket hole configuration;

FIG. 5 is a view similar to that of FIG. 1 showing a system with areceptor package housing forming part of the imaging chamber; and

FIG. 6 illustrates an alternative embodiment for the receptor package in a roll form.

FIG. 1 illustrates an electron radiography system with a sheet 10 fed from a magazine 11 past a corona charger 12, an imaging chamber l3, a developer 14 and a fixer l5, typically with a pair of drive rolls 16 for advancing the sheet.

The magazine 11 is shown in greater detail in FIG. 2 and typically includes a housing 20 with a bottom 21 and cover 22. The cover may be made a push fit on the bottom, with sealing means therebetween (not shown) to provide an air and moisture barrier. A fan or Z folded sheet 24 ispacked in the housing with a leader 25 fed out through a slot 26, preferably with seals 27 at the slot edges. A pair of drive rolls 28 may be mounted in the housing at the slot, with an external drive wheel 29 coupled to one of the rolls for feeding the sheet 25 through the slot.

A plurality of pieces 32 of transparent dielectric plastic is carried on the sheet 24, with the pieces 32 on alternate folds of the sheet 24 so that the sheet 24 serves as a separator between the pieces 32. The sheet 24 preferably has some form of transverse perforation means at each fold, such as punched holes or rouletting or scoring, providing for ease of folding and smooth unfolding as the sheet is fed from the magazine.

The pieces 32 are attached to the sheet 24 by separable means, such as the conventional pressure sensitive adhesive so that the piece 32 is readily peeled from the sheet 24. A section of 'unfoldedsheet is shown in FIG. 3 with the pieces 32 spaced there along between the fold perforations 33. Preferably, the pieces 32 terminate inside the edges of the sheet 24 providing an edge zone or track 35 for engagement by various drive rolls in the system. An alternative configuration is shown in FIG. 4, with sprocket holes'36 along the edges of the sheet 24 for engagement by drive wheel or sprocket.

the sheet 24 has an electrically conducting surface opposite the pieces 32, and may be made of plastic or paper or the like. As indicated in the copending application on Electron Radiographic Receptor, the sheet preferably has a homogeneous character with a resistivity in the order of to 10 ohms per square and may be a conducting paper or a carbon impregnated plastic, both of which materials are available on the market. Alternatively, the body of the sheet may be electrically nonconductive, with an electrically conductive coating on surface opposite the pieces 32. The piece 32 may be a single layer of plastic such as a polyester or a polycarbonate. However, the piece 32 preferably comprises a core layer of polyester or polycarbonate with a thin charge carrier layer of polyethylene or material with similar characteristics.

In operation, the sheet is fed from the magazine 11 past the corona charger 12 where a uniform electrostatic charge is produced on the piece 32 before entering the imaging chamber 13. The sheet drive is stopped while the x-ray exposure is made, using x-ray tube 38 to form the electrostatic charge image. The sheet with the piece carrying the charge image is now driven through the developer 14 and the fixer 15 where the latent image is developed into a visual image and the toner particles are fixed to the plastic piece. The plastic piece with the visual image may now be separated from the sheet, providing the finished picture. Various alternative steps in the process will readily be apparent. After fixing, the sheet 24 may be separated at the per foration line providing continued support for the picture until separation is desired. In other alternatives, a step-by-step developing and fixing process rather than a continuous process may be used. Also, the plastic piece 32 may be separated from the carrier sheet 24 at any time after the exposure step, rather than at the end of the complete developing and fixing operation. Also,

the sheet 24 may be severed after the exposure step with the plastic piece 32 retained thereon during the devloping and fixing.

An alternative embodiment of the electron radiography system is illustrated in FIG. 5, where the receptacle for the receptor package is formed integrally with the imaging chamber rather than being a separator magazine. The folded sheet 24 is inserted into a portion 40 of the imaging chamber 13, as by through a hinged section 41. The sheet is fed past the corona charger 12 and into position between electrodes 43, 44 in the imaging chamber, with edge support drive or idler rolls 46 used as needed. A working gas may be introduced into the imaging chamber through line 48 controlled by valve 49. A liquid seal may be provided at the exit end of the imaging chamber, typically comprising a trough 52 with a baffle 53 projecting into a liquid 54 carried in the trough 52, with the sheet 24 passing through the liquid below the baffle. Several alternative forms of imaging chamber seals are shown in the copending application of Proudian et a1, Ser. No. 424,938, filed Dec. 17, 1973 entitled Imaging Chamber with Liquid Seal, and assigned to the same assignee as the present application.

An alternative configuration for the package is shown in FIG. 6, with the sheet 24 in a roll configuration and having the pieces 32 mounted thereon. The spacing of the pieces 32 along the sheet 24 in the folded configuration and in the rolled configuration depends on the layout of the overall system and may vary considerably from one set up to another.

We claim:

1. A receptor package for an electron radiography system comprising a length of an electrically conducting sheet and a plurality of pieces of transparent dielectric plastic carried thereon with a separable adhesive with the electrical conducting sheet providing a conducting surface for the dielectric plastic pieces and providing for transporting said pieces through an imaging chamber of the electron radiography system.

2. a receptor package as defined in claim 1 having said sheet folded in a Z pattern with said plastic pieces carried on alternate panels of the folded sheet.

3. A receptor package as defined in claim 2 including perforation means at the folds of said sheet.

4. A receptor package as defined in claim 2 including a closed housing having an exit slot and a seal at said slot, with said folded sheet positioned in said housing for feeding out through said slot.

5. A receptor package as defined in claim 4 including a set of drive wheels in said housing adjacent said slot for driving said sheet through said slot.

6. A receptor package as defined in claim 1 with said sheet extending laterally on each side of said plastic pieces providing a drive track at each edge of the sheet.

7. A receptor package as defined in claim 6 with spaced openings along a drive track for engagement by a drive mechanism.

8. A receptor package as defined in claim 1 and having said sheet coiled into a roll.

9. A receptor package as defined in claim 1 wherein each of said plastic pieces comprises a relatively thick transparent dielectric plastic core with one face at said sheet and with a relatively thin dielectric plastic image carrier layer on the opposite core face.

10. A receptor package as defined in claim 1 wherein said sheet comprises a homogeneous body of substantially uniform resistivity.

11. A receptor package as defined in claim 1 wherein said sheet comprises an electrically nonconductive body with an electrically conductive coating on the surface opposite said pieces.

12. A receptor package as defined in claim 1 wherein said sheet has a resistivity in the order of 10 to 10 ohms per square. 

1. A receptor package for an electron radiography system comprising a length of an electrically conducting sheet and a plurality of pieces of transparent dielectric plastic carried thereon with a separable adhesive with the electrical conducting sheet providing a conducting surface for the dielectric plastic pieces and providing for transporting said pieces through an imaging chamber of the electron radiography System.
 2. a receptor package as defined in claim 1 having said sheet folded in a Z pattern with said plastic pieces carried on alternate panels of the folded sheet.
 3. A receptor package as defined in claim 2 including perforation means at the folds of said sheet.
 4. A receptor package as defined in claim 2 including a closed housing having an exit slot and a seal at said slot, with said folded sheet positioned in said housing for feeding out through said slot.
 5. A receptor package as defined in claim 4 including a set of drive wheels in said housing adjacent said slot for driving said sheet through said slot.
 6. A receptor package as defined in claim 1 with said sheet extending laterally on each side of said plastic pieces providing a drive track at each edge of the sheet.
 7. A receptor package as defined in claim 6 with spaced openings along a drive track for engagement by a drive mechanism.
 8. A receptor package as defined in claim 1 and having said sheet coiled into a roll.
 9. A receptor package as defined in claim 1 wherein each of said plastic pieces comprises a relatively thick transparent dielectric plastic core with one face at said sheet and with a relatively thin dielectric plastic image carrier layer on the opposite core face.
 10. A receptor package as defined in claim 1 wherein said sheet comprises a homogeneous body of substantially uniform resistivity.
 11. A receptor package as defined in claim 1 wherein said sheet comprises an electrically nonconductive body with an electrically conductive coating on the surface opposite said pieces.
 12. A receptor package as defined in claim 1 wherein said sheet has a resistivity in the order of 109 to 1012 ohms per square. 